Optical fiber biosensor, biological detection device and detection method thereof

Abstract

An optical fiber biosensor, a biological detection device and a detection method thereof, wherein the optical fiber biosensor comprises an optical fiber, a coupling member and a light guide waveguide, wherein the optical fiber comprises a core and a cladding wrapped outside the core; the coupling member is connected to one end of the optical fiber; the light guide waveguide is connected to the coupling member, and the light guide waveguide forms a first sensing area and a second sensing area, wherein an optical signal generates a first effect in the first sensing area, and a second effect in the second sensing area, wherein the first effect and the second effect are different, and an outgoing light signal after generating the first effect and the second effect is used to obtain data of a target biological molecule. By forming the first sensing area and the second sensing area on the light guide waveguide, two effects can be generated, and by collecting the outgoing light signals of the two effects and performing signal processing, two detection signals of the target biological molecule containing background liquid information can be obtained, and then by setting up simultaneous equations and solving the equations, the data of the target biological molecule can be obtained, thereby eliminating the interference of the background liquid.

Description

Technical Field

[0001] The present application relates to the field of biological detection technology, and in particular to an optical fiber biosensor, a biological detection device and a detection method thereof. Background Art

[0002] Biosensors are devices that use biological substances (such as enzymes, cells, proteins, antibodies, antigens, DNA, etc.) as identifiers and convert biochemical reactions into quantitative physical or chemical signals, thereby realizing the detection and monitoring of life and chemical substances. Biosensors not only involve modern biotechnology and microelectronics, but also involve multiple research fields such as optics and chemistry. They are also widely used in many fields such as medicine and food inspection, especially in medical research and clinical diagnosis. Therefore, they have become a hot topic for scientists in recent years.

[0003] The structure of fiber optic biosensor mainly includes light source, optical fiber, biosensitive element and signal detection system, among which biosensitive element is the key component of the sensor. Commonly used biosensitive elements mainly include antigen antibody, enzyme and nucleic acid. The object to be measured selectively interacts with specific biosensitive element (i.e. antigen antibody or receptor ligand specific binding; nucleic acid molecule base complementary pairing; enzyme specificity on substrate, etc.), and the generated biochemical information modulates the physical properties of light transmitted in the optical fiber, such as light intensity, light amplitude, phase, etc. Therefore, this sensor has strong selectivity and high sensitivity, and can save the tedious work of separating and purifying the test object during the analysis process. However, the spectral behavior of the complexes or products formed above is similar, and it cannot be distinguished by the optical fiber itself. Indicators or markers are often required, such as enzymes, fluorescent substances, acid-base indicators and chromatic chelates. Compared with other biosensors, fiber optic biosensors combine the characteristics of fiber optic sensing, which are specifically reflected in: (1) Due to the good insulation shielding effect of the optical fiber itself, it has strong anti-interference ability and is not disturbed by the surrounding electromagnetic field. (2) No reference electrode is required, the probe can be miniaturized and easy to operate. (3) It can realize remote sensing and perform real-time, online and dynamic detection. (4) It has fast response speed and high sensitivity.

[0004] There are three main types of fiber optic biosensors currently, namely (1) evanescent wave fiber optic biosensors, (2) fiber optic interferometry biosensors, and (3) fiber optic surface plasmon resonance (SPR) biosensors.

[0005] The detection mechanism of the evanescent wave fiber biosensor is as follows: the excitation light generated by the pulsed laser enters the single-mode or multi-mode fiber coupler and then enters the fiber probe, generating an evanescent wave on the probe surface to excite the fluorescent molecules on the antigen-bound labeled antibodies modified on the probe surface, generating fluorescence. Part of the fluorescence is coupled back to the probe and enters the single-mode or multi-mode fiber coupler through the connector. The filter removes the reflected excitation light and allows most of the fluorescence to pass through. The excitation light passes through the photodiode to convert the optical signal into an electrical signal, which is amplified by the phase-locked amplifier and the computer collects and processes the data.

[0006] Fiber interferometric biosensor detection mechanism: External signals acting on the sensing detection part of the interferometric fiber sensor (usually single-mode fiber) will cause the phase change of the interference signal. By detecting the output effect (e.g., light intensity) change caused by the phase change of the light signal, relevant information of the detected object can be obtained. Common fiber interferometric biosensors include Michaelson interferometric fiber sensor, Mach-Zehnder interferometric fiber sensor, Sagnac interferometric fiber sensor, and Fabry-Perot interferometric fiber sensor.

[0007] Fiber SPR biosensor detection mechanism: The light beam is totally reflected at the interface between the core and the cladding. The change in the interface refractive index leads to the difference in phase velocity and group velocity. The leaked evanescent wave causes the free electrons inside the metal deposited on the surface of the optical fiber to oscillate. This collective motion of free electrons appears in the form of surface plasma waves at a specific frequency. Changes in the surrounding medium will affect the effective refractive index and propagation loss of the optical fiber. The sensing signal can be obtained by observing the changes in the resonance frequency of the optical fiber surface plasma.

[0008] Evanescent wave fiber biosensor has high selectivity, but the biological modification and biological detection steps are cumbersome; fiber interference biosensor has a simple principle and is easy to make, but the sensitivity is insufficient, and the fiber after micro-nano processing is fragile, which is not conducive to detection and use; fiber surface plasmon resonance biosensor has high sensitivity, but the production is relatively complicated. Moreover, these three types of fiber biosensors cannot eliminate the background interference of liquid detection of biological samples to be tested. For example, when detecting target cancer factors in serum, the serum background will bring background interference signals to the sensor. We should try to eliminate the background interference signals of serum and leave only the detection signal of the detection target. Summary of the invention

[0009] The purpose of the present application is to provide a fiber optic biosensor and a detection method based on the fiber optic biosensor to solve the problem that the current fiber optic biosensor cannot eliminate the background interference of liquid detection of the biological sample to be tested.

[0010] To achieve the purpose of this application, this application provides the following technical solutions:

[0011] In a first aspect, the present application provides an optical fiber biosensor, comprising: an optical fiber, comprising a core and a cladding wrapped around the core; a coupling element, connected to one end of the optical fiber; a light guide waveguide, connected to the coupling element, the light guide waveguide forming a first sensing area and a second sensing area, an optical signal produces a first effect in the first sensing area, and an optical signal produces a second effect in the second sensing area, the first effect and the second effect are different, and the outgoing optical signal after the first effect and the second effect are produced is used to obtain data of target biological molecules.

[0012] In one embodiment, the first effect is any one of a surface plasmon resonance effect, a light absorption effect at a characteristic wavelength, and a Raman sensing effect; the second effect is any one of a multimode inter-mode interference effect, a Mach-Zehnder interference effect, a Michelson interference effect, a Fabry-Perot interference effect, and a Segnac interference effect.

[0013] In one embodiment, the light guide waveguide is in the shape of a column extending in a straight line, and its cross section is circular or polygonal, and the first sensing area and the second sensing area are separated along the length direction of the light guide waveguide.

[0014] In one embodiment, a semiconductor layer or a metal layer rich in free electrons is deposited on the first sensing region.

[0015] In one embodiment, both the first sensing area and the second sensing area are formed with a biofunctional membrane, and the biofunctional membrane is used to react with a designated target biomolecule.

[0016] In one embodiment, a reflector is further included, and the reflector is arranged at an end of the light-guiding waveguide away from the coupling element.

[0017] In a second aspect, the present application also provides a biological detection device, comprising a light source, a light detector and an optical fiber biosensor described in any one of the various embodiments of the first aspect, wherein the light source is used to input an optical signal into the optical fiber, and the light detector is used to receive an output optical signal from the optical fiber.

[0018] In one embodiment, it also includes a low-pass filter and a band-pass filter, wherein the low-pass filter is used to extract the low-frequency signal of a single absorption peak in the output light signal of the optical fiber biosensor to obtain the first data, and the band-pass filter is used to extract the periodically varying signal of a fixed frequency in the output light signal of the optical fiber biosensor to obtain the second data.

[0019] In a third aspect, the present application further provides a biological detection method, which is based on the optical fiber biosensor described in any one of the various embodiments of the first aspect, and the biological detection method comprises: immersing a light guide waveguide in a liquid to be detected; injecting a light signal into the optical fiber, wherein the light signal is coupled into the light guide waveguide through a coupling member and propagates; the light signal generates a surface plasmon resonance effect in a first sensing region of the light guide waveguide and a multimode inter-mode interference effect in a second sensing region of the light guide waveguide; receiving an outgoing light signal from the light guide waveguide, and obtaining a total change α of the sensing signal of the surface plasmon resonance effect from the light signal. SPR , the total change α of the sensing signal of the multi-mode inter-mode interference effect is obtained from the optical signal MMI ; According to α SPR and α MMI Get data of target biomolecules.

[0020] In one embodiment, the liquid to be tested comprises a target biomolecule and a background liquid, the surface plasmon resonance effect has a response sensitivity of S1 to a signal of the target biomolecule, the surface plasmon resonance effect has a response sensitivity of S2 to an interference signal of the background liquid, the multimode intermodal interference effect has a response sensitivity of S3 to a signal of the target biomolecule, and the multimode intermodal interference effect has a response sensitivity of S4 to an interference signal of the background liquid, wherein S1, S2, S3 and S4 are determined by experiments;

[0021] Assume that the target amount of the target biomolecule is m, and the interference amount of the background liquid is m';

[0022] The simultaneous matrix equations are as follows:

[0023]

[0024] m and m' are found according to the matrix equation.

[0025] By forming a first sensing area and a second sensing area on the light-guiding waveguide, two effects can be produced. By collecting the output light signals of the two effects and performing signal processing, two detection signals of the target biological molecules containing background liquid information can be obtained. Then, by simultaneously setting equations and solving the equations, the data of the target biological molecules can be obtained, thereby eliminating the interference of the background liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 is a schematic diagram of an optical fiber biosensor according to an embodiment;

[0028] Figure 2 is a schematic diagram of a biological detection device according to an embodiment;

[0029] Figure 3 is a partial flow chart of a biological detection method of an embodiment;

[0030] Figure 4 The figure is a schematic diagram of the signal processing result of the biological detection method of an embodiment.

[0031] Description of reference numerals:

[0032] 10-fiber biosensor, 11-optical fiber, 111-core, 112-cladding, 12-coupling element, 13-light-guiding waveguide, 131-first sensing area, 132-second sensing area, 14-biofunctional membrane, 15-reflecting element;

[0033] 21-target biomolecule, 22-background fluid;

[0034] 31 - light source, 32 - input optical fiber, 33 - light splitter, 34 - output optical fiber, 35 - optical detector. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there can be a central component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time.

[0037] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this application and in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this application includes any and all combinations of one or more of the related listed items.

[0038] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0039] Please refer to Figure 1 An embodiment of the present application provides a fiber optic biosensor 10 , comprising an optical fiber 11 , a coupling element 12 , and a light-guiding waveguide 13 .

[0040] The optical fiber 11 includes a core 111 and a cladding 112 wrapped around the core 111. The core 111 is used to transmit an optical signal, which is a light beam. When the light beam is transmitted in the core 111, total reflection occurs at the cladding 112. When the light beam propagates in the optical fiber 11, there is almost no attenuation, and the external light does not enter the optical fiber 11 to propagate. Therefore, the optical fiber 11 has good stability and anti-interference. Optionally, the optical fiber 11 is a single-mode optical fiber.

[0041] The coupling element 12 is connected to one end of the optical fiber 11. The coupling element 12 is used to couple the optical signal in the optical fiber 11 to the light guide waveguide 13, and can modulate the parameters of the optical signal. For example, the coupling element 12 modulates the optical wave mode from the fundamental mode to multiple high-order modes, and the optical signals in the multiple high-order modes can generate inter-mode interference when transmitted in the light guide waveguide 13.

[0042] The light-guiding waveguide 13 is connected to the coupling element 12, and the light-guiding waveguide 13 forms a first sensing area 131 and a second sensing area 132. The light signal generates a first effect in the first sensing area 131, and the light signal generates a second effect in the second sensing area 132. The first effect and the second effect are different. The outgoing light signal after generating the first effect and the second effect is used to obtain data of the target biological molecule 21.

[0043] The conventional optical fiber biosensor 10 can only produce one effect and cannot eliminate the interference of the background fluid 22 .

[0044] In the present application, by forming a first sensing area 131 and a second sensing area 132 on the light-guiding waveguide 13, two effects can be produced. By collecting the output light signals of the two effects and performing signal processing, two detection signals of the target biological molecules 21 containing the information of the background liquid 22 can be obtained. Then, by simultaneously setting equations and solving the equations, the data of the target biological molecules 21 can be obtained, thereby eliminating the interference of the background liquid 22.

[0045] There are existing fiber optic biosensors based on a single sensing principle, such as evanescent wave fiber optic biosensors, fiber optic interferometry biosensors, fiber optic SPR biosensors, etc. These sensors will inevitably detect the liquid detection background signal (interference signal) of the biological sample while detecting the target biological molecules. Due to the limitation of a single sensing principle, these sensors cannot distinguish between the target signal and the interference signal, which brings certain difficulties to the accuracy of detection.

[0046] The optical fiber biosensor 10 with dual sensing effects proposed in the present application can simultaneously stimulate dual sensing effects and be used independently to detect biological samples. It can separate and demodulate the target biological molecule 21 signal and the interference signal of the background liquid, thereby achieving high-accuracy detection of the target biological molecule 21.

[0047] Optionally, the first effect is any one of the surface plasmon resonance (SPR) effect, the light absorption effect of two-dimensional materials or other special materials on characteristic wavelengths, and the Raman sensing effect. The second effect is any one of the multi-mode interferometer (MMI) effect, the Mach-Zehnder interference effect, the Michelson interference effect, the Fabry-Perot interference effect, and the Sagnac interference effect. The specific contents of the above-mentioned various sensing effects are not repeated here, and the relevant contents in the prior art may be referred to, and this application is not limited.

[0048] Preferably, the first effect is the SPR effect, and the second effect is the MMI effect.

[0049] Please continue to refer to Figure 1 The light guide waveguide 13 is in the shape of a column extending in a straight line, and its cross section is circular or polygonal. The surface extending along the length direction of the light guide waveguide 13 separates the light guide waveguide 13 into a first sensing area 131 and a second sensing area 132 .

[0050] Specifically, the optical waveguide 13 (optional waveguide) is a dielectric device that guides light waves to propagate therein, also known as a dielectric optical waveguide. The optical waveguide 13 is made of a transparent material, and can be made of materials such as quartz glass. The shape of the optical waveguide 13 is cylindrical, and the cross section is circular, triangular, quadrilateral, pentagonal, hexagonal, octagonal, etc. Preferably, the cross section of the optical waveguide 13 is circular, regular triangle, rectangular (further preferably square), parallelogram (further preferably rhombus), regular pentagon, regular hexagon, regular octagon, etc. Optionally, the first sensing area 131 and the second sensing area 132 are separated by a plane, and the plane passes through the center line of the length direction of the optical waveguide 13. That is, the plane divides the optical waveguide 13 into two halves of the same length. Alternatively, the first sensing area 131 and the second sensing area 132 may also be separated by a non-planar separation, for example, separated by a surface with a curved or broken line cross section. No matter how it is divided, one side of the light-guiding waveguide 13 in the length direction needs to be the first sensing area 131, and the other side needs to be the second sensing area 132. When the light beam passes through the light-guiding waveguide 13, sensing effects are synchronously generated in the first sensing area 131 and the second sensing area 132, and the optical signal synchronously carries information of the first effect and the second effect.

[0051] In one embodiment, please refer to Figure 1 The first effect generated by the first sensing area 131 is the SPR sensing effect. The first sensing area 131 is deposited with a semiconductor layer (not shown in the figure) or a metal layer containing rich free electrons (not shown in the figure) to form an SPR sensing layer for stimulating the SPR sensing effect.

[0052] When the second effect generated by the second sensing area 132 is the MMI sensing effect, the second sensing area 132 is not processed, that is, the light guide waveguide 13 directly forms the second sensing area 132. When the light beam is coupled from the optical fiber 11 to the light guide waveguide 13 through the coupling element 12, the light wave mode excites multiple high-order modes from the fundamental mode, and the multiple high-order modes will generate inter-mode interference during the transmission process of the light guide waveguide 13, thereby exciting MMI sensing. Therefore, the half side cylindrical surface of the light guide waveguide 13 where the SPR sensing layer is not deposited (that is, the second sensing area 132) forms an MMI sensing area.

[0053] It is understandable that the first sensing region 131 and the second sensing region 132 may be provided with structures for stimulating corresponding effects according to different sensing effects, such as the first sensing region 131 may be provided with an SPR sensing layer for stimulating the SPR effect, and the second sensing region 132 may be provided with no SPR sensing layer for stimulating the MMI effect. In addition to this configuration, when the first sensing region 131 and the second sensing region 132 generate other effects, the structures for stimulating corresponding effects are not limited.

[0054] In one embodiment, please refer to Figure 1 The first sensing area 131 and the second sensing area 132 are both formed with a biofunctional membrane 14, which is used to react with the designated target biomolecule 21 and can be used to specifically detect the target biomolecule 21. The biofunctional membrane 14 is an exclusive capture membrane for the target biomolecule 21, which can only capture the target biomolecule 21 and has no reaction to other biomolecules. By providing the biofunctional membrane 14, the light beam can collect the light signal containing the target biomolecule 21 in the first sensing area 131 and the second sensing area 132 according to their respective sensing effects.

[0055] In one embodiment, please continue to refer to Figure 1 The optical fiber biosensor 10 further includes a reflector 15, which is disposed at one end of the light guide waveguide 13 away from the coupling element 12. The reflector 15 is made of a material with high reflectivity, such as a metal element, a metal alloy, etc., without limitation. The reflector 15 is disposed on the end face of the light guide waveguide 13, and the optical signal carrying the first effect and the second effect is reflected by the reflector 15. The optical signal returns along the original transmission path, passes through the first sensing area 131 and the second sensing area 132 again, and generates the first effect and the second effect again, which can enhance the information of the target biological molecule 21 of the optical signal, and facilitates subsequent signal processing.

[0056] In conventional technology, after the optical signal passes through the light guide waveguide 13, it is emitted from the end of the light guide waveguide 13 facing away from the coupling element 12, without the reflector 15, that is, it is emitted directly without reflection. Compared with conventional technology, to collect information of the same target biological molecule 21, the length of the light guide waveguide 13 of the present application can be shortened by half, thereby reducing the size of the optical fiber biosensor 10, and at the same time, it can also reduce the detection sample and save biological samples. In addition, since only the reflector 15 is provided at one end of the light guide waveguide 13, the optical fiber biosensor 10 can be designed as an insertable microprobe, which is easy to use.

[0057] Obviously, in other embodiments of the present application, the reflector 15 may not be provided, but a conventional technical solution may be adopted, that is, the optical signal is emitted from the end of the optical fiber 11 facing away from the coupling element 12.

[0058] Please refer to Figure 1 and Figure 2 The embodiment of the present application also provides a biological detection device, including a light source 31, a light detector 35, and the optical fiber biosensor 10 of any of the above embodiments. The light source 31 and the light detector 35 are both connected to the end of the optical fiber 11 of the optical fiber biosensor 10 away from the coupling member 12, the light source 31 is used to input an optical signal to the optical fiber 11, and the light detector 35 is used to receive the output optical signal of the optical fiber 11.

[0059] Specifically, in this embodiment, a solution of setting a reflector 15 is adopted. The light source 31 is connected to the spectrometer 33 through the input optical fiber 32, the light detector 35 is connected to the spectrometer 33 through the output optical fiber 34, and the optical fiber 11 of the optical fiber biosensor 10 is connected to the spectrometer 33. The light source 31 is a laser, which is used to generate a laser beam. The laser beam is transmitted to the spectrometer 33 through the input optical fiber 32. The spectrometer 33 is spectroscopically coupled to the optical fiber 11 of the optical fiber biosensor 10 to become an incident light signal. The light signal returned from the optical fiber 11 of the optical fiber biosensor 10 is an output light signal. After the output light signal is transmitted to the spectrometer 33, the spectrometer 33 is spectroscopically coupled to the light detector 35 to realize the collection of the light signal containing the information of the target biological molecule 21.

[0060] In an embodiment without the reflective element 15, the light source 31 and the light detector 35 are respectively disposed at the two ends of the light-guiding waveguide 13, that is, the light source 31 is connected to the optical fiber 11 of the optical fiber biosensor 10 to emit an incident light signal; the light detector 35 can be connected to one end of the light-guiding waveguide 13 away from the coupling element 12 through another optical fiber to receive the outgoing light signal.

[0061] In one embodiment, please refer to Figures 1 to 3 The biological detection device also includes a low-pass filter (not shown in the figure) and a band-pass filter (not shown in the figure). The low-pass filter is used to extract the low-frequency signal of the single absorption peak in the output light signal of the optical fiber biosensor 10 to obtain the first data. The band-pass filter is used to extract the periodic variation signal of the fixed frequency in the output light signal of the optical fiber biosensor 10 to obtain the second data.

[0062] Specifically, in the embodiment where the reflector 15 is provided, please refer to Figure 2 The low-pass filter and the band-pass filter can be arranged between the light splitter 33 and the light detector 35, or can be arranged inside or after the light detector 35. Figure 1 and Figure 2 In an embodiment where the reflective element 15 is not provided, the end of the light guide waveguide 13 away from the coupling element 12 is connected to the light detector 35 through an optical fiber, and the low-pass filter and the band-pass filter can be provided between the light guide waveguide 13 and the light detector 35, or can be provided inside or after the light detector 35.

[0063] Please refer to Figure 3 and Figure 4 , the first effect of the optical fiber biosensor 10 is the SPR sensing effect, the second effect is the MMI sensing effect, and the low-pass filter and the band-pass filter are arranged after the optical detector 35 as an example to illustrate the simple process of signal extraction: after the outgoing light signal is collected by the optical detector 35, it is input into the low-pass filter, and the low-pass filter extracts the low-frequency signal of the single absorption peak in the outgoing light signal, and outputs the SPR sensing signal αSPR , the other signals continue to be input into the bandpass filter, which extracts the periodic variation signal with a fixed frequency and outputs the MMI sensor signal α MMI , the remaining invalid signals are output directly. Figure 4 The waveform image of the initial signal of the output optical signal and the waveform image of the extracted signal after passing through the low-pass filter and the band-pass filter are shown.

[0064] By setting a low-pass filter and a band-pass filter, the signals of the first effect and the second effect can be extracted to obtain detection data, which is convenient for subsequent acquisition of data of the target biological molecule 21.

[0065] This embodiment adopts light wavelength modulation. In other embodiments, light intensity modulation, light incident angle modulation, etc. may also be adopted, without specific limitation.

[0066] The present application also provides a biological detection method, please refer to Figure 1 and Figure 2 The biological detection method is based on the optical fiber biosensor of any of the aforementioned embodiments, and the biological detection method includes steps S10-S50.

[0067] S10, immersing the light guide waveguide 13 into the liquid to be tested;

[0068] S20, an optical signal is incident on the optical fiber 11, and the optical signal is coupled into the light guide waveguide 13 through the coupling element 12 for propagation;

[0069] S30, the optical signal generates a surface plasmon resonance (SPR) effect in the first sensing region 131 of the optical waveguide 13, and generates a multimode mode interference (MMI) effect in the second sensing region 132 of the optical waveguide 13;

[0070] S40, receiving the outgoing light signal from the light guide waveguide 13, and obtaining the total change amount α of the sensing signal of the SPR effect from the light signal SPR , the total change of the sensing signal of the MMI effect obtained from the optical signal α MMI ;

[0071] S50, according to α SPR and α MMI The data of the target biomolecule 21 is obtained.

[0072] In S10, the liquid to be tested contains target biological molecules 21 and background liquid 22, and the light guide waveguide 13 contains a first sensing area 131 and a second sensing area 132. Through steps S20 and S30, SPR effect and MMI effect are generated, and through step S40, two signals, namely α SPR and α MMI, both signals are related to the target biomolecule 21 and the background liquid 22. In step S50, according to α SPR and α MMI The data of the target biomolecule 21 and the background liquid 22 are obtained. Specifically, for the two unknown quantities of the target biomolecule 21 data to be solved and the interference data of the background liquid 22, two sets of related data are required, and α SPR and α MMI It contains two sets of related data, which can be solved by simultaneous equations, so that the target biological molecule 21 can be detected and the interference of the background liquid 22 is eliminated.

[0073] In a specific embodiment, the response sensitivity of the SPR effect to the signal of the target biological molecule 21 is S1, the response sensitivity of the SPR effect to the interference signal of the background liquid 22 is S2, the response sensitivity of the MMI effect to the signal of the target biological molecule 21 is S3, and the response sensitivity of the MMI effect to the interference signal of the background liquid 22 is S4, wherein S1, S2, S3 and S4 are determined by experiments.

[0074] Assume that the target amount of the target biomolecule 21 is m, and the interference amount of the background liquid 22 is m′.

[0075] The simultaneous matrix equations are as follows:

[0076]

[0077] In order to eliminate the interference of the interference quantity m' and obtain the accurate target quantity m, and because the SPR and MMI dual sensing effects of the optical fiber biosensor 10 have different signal responses to m and m', we set the response sensitivity of the SPR sensing effect to m to S1, the response sensitivity of the SPR sensing effect to m' to S2, the response sensitivity of the MMI sensing effect to m to S3, and the response sensitivity of the MMI sensing effect to m' to S4. In the biological sample to be tested with trace biomolecule changes, it can be considered that the dual sensing effect has linear responses to m and m'. Therefore, the accurate m and m' can be solved by the simultaneous matrix equations.

[0078] In the matrix equation, S1, S2, S3 and S4 are known quantities determined by experiments, and α SPR and α MMI It is measured by the optical fiber biosensor 10 and is also a known quantity, so m and m′ can be calculated according to the matrix equation, thereby detecting and obtaining the required data m of the target biomolecule 21 and excluding the interference data m′ of the background liquid 22 .

[0079] A specific embodiment is introduced below.

[0080] Please refer to Figure 1The target biological molecule 21 in the background liquid 22 detected by the optical fiber biosensor 10 provided by the present application is C-reactive protein. The light guide waveguide 13 is cylindrical, 5 mm in length, 80 μm in diameter, and made of quartz glass. The first sensing area 131 is deposited with a 50 nm gold thin film sensing layer as an SPR sensing layer, the reflector 15 is a 500 nm silver film, and the biofunctional film 14 is a C-reactive protein antibody.

[0081] In this embodiment, a wavelength modulation method is used to obtain the sensing signal. Figure 4 As shown, after the detection spectrum signal of the optical fiber biosensor 10 for detecting C-reactive protein passes through the low-pass filter, the low-frequency component SPR spectrum signal is filtered out; by adjusting the bandpass band of the bandpass filter, the bandpass band of the appropriate MMI spectrum signal is found, and the bandpass filter also filters out the MMI spectrum signal with a certain frequency. The lowest point of the normalized light intensity of the SPR and MMI spectrum signals is tracked respectively, that is, the trough of the SPR spectrum signal and the lowest trough of the MMI spectrum signal. When the sample concentration changes, the light wavelength position of the trough will also move accordingly.

[0082] C-reactive protein was detected in phosphate buffered saline (PBS), the background interference signal was the signal of PBS, and the target molecule signal was the signal of C-reactive protein. The experimental results showed that the response sensitivity of SPR sensor effect to C-reactive protein was S1=0.48nm / (μg / mL), the response sensitivity of SPR sensor effect to PBS was S2=3.10nm / (1 times PBS), the response sensitivity of MMI sensor effect to C-reactive protein was S3=0.15nm / (μg / mL), and the response sensitivity of MMI sensor effect to PBS was S4=0.12nm / (1 times PBS). 1nm / (μg / mL) means that for every 1μg / mL change in the concentration of C-reactive protein, the wavelength of light will move by 1nm. 1nm / (1 times PBS) means that for every 1-fold change in the concentration of PBS, the wavelength of light will move by 1nm.

[0083] Then through the formula (in this case, α in the formula SPR is the total change of the measured SPR sensor signal, α MMI is the total variation of the measured MMI sensor signal, m is the concentration of C-reactive protein, and m' is the concentration of PBS):

[0084]

[0085] Can be written as For samples with unknown CRP concentration and PBS as the background solution, as long as α SPR and α MMI The concentration of the target substance C-reactive protein can be calculated.

[0086] In this embodiment, C-reactive protein is detected. When other target biological molecules 21 are detected, it is only necessary to change the biological functional membrane 14 without limitation.

[0087] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" are based on the orientation or positional relationship described in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or original referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0088] What is disclosed above is only a preferred embodiment of the present application, and it certainly cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiment and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. An optical fiber biosensor, It is characterized in that include: An optical fiber, comprising a core and a cladding wrapped around the core; A coupling member connected to one end of the optical fiber; a light guide waveguide connected to the coupling element, the light guide waveguide forming a first sensing area and a second sensing area, the light signal generates a first effect in the first sensing area, and the light signal generates a second effect in the second sensing area, the first effect and the second effect are different, and the outgoing light signal after generating the first effect and the second effect is used to obtain data of the target biomolecule; The light guide waveguide is in a straight-line column shape, and a surface extending along the length direction of the light guide waveguide separates the light guide waveguide into the first sensing area and the second sensing area, a center line of the light guide waveguide in the length direction is located on the surface, and one end of the first sensing area and one end of the second sensing area are both connected to the coupling member; The first effect is a surface plasmon resonance effect, and the second effect is a multi-mode inter-mode interference effect; The coupling element is used to modulate the light wave mode from the fundamental mode to a plurality of high-order modes, and the optical signals of the plurality of high-order modes can generate inter-mode interference when transmitted in the light-guiding waveguide.

2. The optical fiber biosensor according to claim 1, It is characterized in that The cross section of the light guiding waveguide is circular or polygonal.

3. The optical fiber biosensor according to claim 1, It is characterized in that The first sensing region is deposited with a semiconductor layer or a metal layer rich in free electrons.

4. The optical fiber biosensor according to claim 1, It is characterized in that The first sensing area and the second sensing area are both formed with biofunctional membranes, and the biofunctional membranes are used to react with designated target biomolecules.

5. The optical fiber biosensor according to any one of claims 1 to 4, It is characterized in that A reflector is also included, and the reflector is arranged at an end of the light-guiding waveguide away from the coupling element.

6. A biological detection device, It is characterized in that It comprises a light source, a light detector and the optical fiber biosensor according to any one of claims 1 to 5, wherein the light source is used to input an optical signal into the optical fiber, and the light detector is used to receive an output optical signal from the optical fiber.

7. The biological detection device according to claim 6, It is characterized in that It also includes a low-pass filter and a band-pass filter, wherein the low-pass filter is used to extract the low-frequency signal of a single absorption peak in the output light signal of the optical fiber biosensor to obtain the first data, and the band-pass filter is used to extract the periodically changing signal of a fixed frequency in the output light signal of the optical fiber biosensor to obtain the second data.

8. A biological detection method, It is characterized in that The biological detection method is based on the optical fiber biosensor according to any one of claims 1 to 5, and the biological detection method comprises: Immerse the light-guiding waveguide into the liquid to be tested; An optical signal is injected into the optical fiber, and the optical signal is coupled into the optical waveguide through the coupling element for propagation; The optical signal generates a surface plasmon resonance effect in the first sensing region of the optical waveguide, and generates a multi-mode inter-mode interference effect in the second sensing region of the optical waveguide; receiving an outgoing light signal from the light guide waveguide, and obtaining a total variation of a sensing signal of the surface plasmon resonance effect from the light signal; , obtaining the total change of the sensing signal of the multi-mode inter-mode interference effect from the optical signal ; according to and Get data of target biomolecules.

9. The detection method according to claim 8, It is characterized in that The liquid to be tested includes a target biomolecule and a background liquid, and the response sensitivity of the surface plasmon resonance effect to the signal of the target biomolecule is S 1 The response sensitivity of the surface plasmon resonance effect to the interference signal of the background liquid is S 2 The response sensitivity of the multimode intermodal interference effect to the signal of the target biomolecule is S 3 The response sensitivity of the multi-mode inter-mode interference effect to the interference signal of the background liquid is S 4 , where S 1 , S 2 , S 3 and S 4 Determined by experiment; Assume that the target amount of the target biomolecule is m, and the interference amount of the background liquid is m'; The simultaneous matrix equations are as follows: m and m' are found according to the matrix equation.

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